Regular Expression TLD email

gistfile1.cs

using System;
using System.Globalization;
using FluentSharp.CoreLib;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Text.RegularExpressions;
namespace RegExTest
{
    [TestClass]
    public class RegExTest
    {
        private const string RegExPattern =@"^(?("")("".+?(?<!\\)""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" +
                                           @"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$";


        private const int MaxIterations = 100000;

        [TestMethod]
        public void Email_Unicode_TLD()
        {

            string input = "admin@استفتاء.مصر";

            //REplacing unicode TLD https://msdn.microsoft.com/en-us/library/01escwtf%28v=vs.110%29.aspx
            input = Regex.Replace(input, @"(@)(.+)$",this.DomainMapper,RegexOptions.None, TimeSpan.FromMilliseconds(200));

            Assert.AreEqual(input,"[email protected]");

            Assert.IsTrue(Regex.IsMatch(input, RegExPattern,RegexOptions.None,TimeSpan.FromSeconds(1)));
        }
        [TestMethod]
        public void Email_Long_TLD_Is_Supported()
        {
            const string input = "[email protected]";
            var result = Regex.IsMatch(input, RegExPattern, RegexOptions.IgnoreCase, TimeSpan.FromSeconds(1));
            Assert.IsTrue(result);
        }
        [TestMethod]
        public void Email_Is_Valid()
        {
            const string input = "[email protected]";
            var result = Regex.IsMatch(input, RegExPattern, RegexOptions.IgnoreCase, TimeSpan.FromSeconds(1));
            Assert.IsTrue(result);
        }
        [TestMethod]
        public void Email_Is_Invalid()
        {
            const string input = "mhidalgo";
            var result = Regex.IsMatch(input, RegExPattern, RegexOptions.IgnoreCase, TimeSpan.FromSeconds(1));
            Assert.IsFalse(result);
        }

        [TestMethod]
        public void FuzzInput()
        {
            for (int x = 0; x < MaxIterations; x++)
            {
                //Generates a random input of 50 characters per iteration
                var fuzzString = 10.randomChars() + "".random_Email() + 15.randomChars();
                Assert.IsTrue(fuzzString.Length == 50);
                Regex.IsMatch(fuzzString,RegExPattern,RegexOptions.IgnoreCase,TimeSpan.FromSeconds(1));
            }
        }

        private string DomainMapper(Match match)
        {
            // IdnMapping class with default property values.
            var idn = new IdnMapping();

            string domainName = match.Groups[2].Value;
            try
            {
                domainName = idn.GetAscii(domainName);
            }
            catch (ArgumentException)
            {
                
            }
            return match.Groups[1].Value + domainName;
        }
    }
}